Convincing Castle
by stanaticfanatic
Summary: Insert for 6x17, 'In the Belly of the Beast'. What if Gates hadn't called and Beckett was able to convince Castle on her choice of font? Definitely M-rated, pure smut with a touch of Caskett fluff! No major spoilers for episode.


**_A/N: so I've already written a post-ep for this episode, but then I (read: my dirty mind) got thinking - how would Beckett convince Castle? Just some smutty fluff, don't read it if it's not your thing!_**

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"What we both need right now is a really good _font_." And with that, Kate Beckett grabbed her fiancé by the hand and pulled him up, dragging him into the bedroom behind her. Spinning around, she wrapped her arms around his neck and kissed him hard.

Castle was surprised at her sudden intrusion but soon recovered, and he started kissing her back, their tongues tangling in a battle for control. They both knew it wasn't a 'font' she was suggesting they needed right now, but he wasn't going to turn down an opportunity for his sexy as hell fiancé to try and convince him anyway. Truth be told, if that font put a smile on her face, he'd agree to it whether he liked it or not. _God he was such a sap where Kate Beckett was concerned._

"Castle," she said between kisses, snapping him out of his reverie, "less thinking more doing." She grabbed his hand and pulled him down to the bed on top of her, lips still attached. He could get used to this.

Needing to get her naked, he stripped her of her pyjamas and she helped him remove his own clothing. She flipped them over so she that she was straddling him and she ground her hips into his length which was hardening beneath her.

"Shit, Kate," he gasped, tearing his lips from her mouth and moving to her neck instead. "Unless you want this to be over before it's already started you're gonna have to slow down."

"Nope." Was all she said, biting down hard on his neck, causing him to buck his hips up into her instinctively. She sucked the skin into her mouth and soothed it with her tongue, swirling it round and round in circles in her mouth.

Castle couldn't touch enough of her. His hands roamed over her body, up and down her back and over her rather impressive backside. Sliding his hands down her front, he brushed his fingertips over her nipples and they hardened immediately. She groaned into his neck and pressed her hips into him again. Castle continued the movement of his hands, one sliding down her stomach and towards her wetness. He used his index finger to part her folds, sliding it through her heat. _Gives Nikki _Heat_ a whole new meaning_, he thought.

"Castle.." She hissed. "Stop..oh god you need to stop!"

"Why Kate? You seem to be enjoying yourself from my point of view." He smirked, his finger sliding over her clit causing her to cry out and slam her hips into his hand.

"No.." She gasped, reaching down to remove his hand. "_I'm_ supposed to be convincing _you_...this is about _you_!" She managed to get out, she was so turned on right now that it had been nearly impossible to drag Castle's hand away, but she'd managed it. Just. "Now, you going to keep your hands to yourself?" She asked. She could tell from the flash in his eyes that he was thinking about her handcuffs. "Mind out of the gutter, Castle."

"Babe, we're both naked and you're on top of me. You can see how turned on I am right now and I'm willing to bet you're just as turned on as me, you'd be disappointed if my mind was anywhere _other_ than the gutter."

He had a point. Jesus this convincing was going to be harder than she thought, she was getting desperate for him already. _Focus, Beckett_. "Hmm, well let's see if I can put different thoughts in your mind.." She said, beginning to trail her lips over his chest, covering every inch of him that she possibly could. Reaching his nipples, she darted out her tongue and ran it around one in circles. Castle gasped and bucked his hips again, his hands grabbing her hips and holding her tightly. Kate bit down on a nipple and trailed a hand down to his rather impressive length.

"Holy sh-" he gasped, "oh god, Kate.."

"What is it Castle?" She teased, removing her hand and sliding back up his body to her original position.

"You little-" she cut him off with a deep kiss, her tongue sliding over his bottom lip before she pulled it into her mouth and bit down lightly, satisfied when she heard him groan into her mouth.

Moving down again, she went further this time, her lips trailing kisses over his stomach and biting lightly on his hipbones.

Castle gripped the sheets tightly, she was torturing him. His rock hard erection was right next to her face, all she would have to do is move an inch to the right and-

Just as he thought she was about to relieve him of some of his tension, she bypassed his cock and moved her mouth to his thighs. _Jesus, if she didn't let him come soon he was going to pin her to the bed and fuck her until she couldn't move._ But he knew how much she wanted to be in charge, wanted to convince him of her favourite 'font'. _Oh who was he kidding_, this had stopped being about the font the minute he'd suggested she try and convince him.

Castle was brought back to reality when Beckett started nipping at his inner thigh, inching closer and closer to his cock with every bite. He was trying desperately to not thrust his hips up, desperate to please her and let her do what _she_ wanted. Oh god, he was ridiculous. They'd come in here so she could convince _him_ on what she wanted and he just wanted her to be happy. He was so in love it hurt. Just like something else that was becoming slightly painful..

"Beckett..Kate..please," he gasped, "I'm..oh god-"

"You're what, Castle? Struggling to put together a coherent sentence?" She said, hovering her mouth over his cock.

"Yessss.." He hissed, oh _god_, she was so close to him..

"Hmm, too bad." She shrugged, passing over him and putting her lips on his other thigh to a muttered _shit_ from her fiancé. She upped the ante this time, biting harder than she had on the other thigh, leaving bruises that would remind him of this afternoon for a good few days.

Inching closer and closer, she thought it was time to let him out of his misery. Slipping her tongue out from between her lips, she ran her tongue up the underside of his length and he almost lost it there and then.

"Oh fuck..oh my..Kate!" He cried out, sheets bunching in his fists. She smiled, pleased with herself at what she was putting him through.

Taking the head into her mouth, she swirled her tongue around it, her hands braced on his hips. With each suck, she took a little bit more of his length into her mouth and he was writhing in pleasure underneath her. _I did this_, she thought, _I got him this worked up and desperate. _These thoughts made her happy, she was extremely pleased at the fact that she could make him like this, no one else, her.

Taking him further into her mouth, she stopped when the tip of his cock brushed the back of her throat. She sucked hard, her cheeks hollowing with the effort and he groaned in ecstasy when she massaged his balls with her hand. "Oh my god..Kate please." He growled. "Oh baby don't stop..please.." His thrust his hips up, hissing when he pushed further down her throat.

Kate could feel the moment he was about to come, his balls beginning to tighten in anticipation and she decided she wasn't done yet, she was having way too much fun. Releasing him with a loud _pop_, she climbed back up his body, legs spread wide over his still rock hard erection.

"Jesus fucking Christ, Kate. You're killing me!" He said. He couldn't believe she'd stopped when she had, not then.. "I was so close, babe, so close.."

"Oh, you were, were you?" She teased, her lips latching onto his neck.

"Yes I was Kate and you know, I was. You're evil, woman. Evil I tell you!" His hips thrust upwards again, desperately seeking out her hot, wet heat.

"Oh I wouldn't go that far, Castle, you are marrying me after all." She said, using her legs resting on the bed as leverage to lift herself off of him slightly, not wanting to let him get his own way just yet.

"Come back here," he growled, his hands gripping onto her hips to pull her back down trying once again to thrust into her.

"Castle," she warned, "this is about you, remember, not me."

"Babe, I'm telling you, _that_ would not be a disappointment. I just hope you're close because five seconds inside of you and I'll come apart.." He gasped. "I just want this to be good for you, too."

Kate bit back a smile. Even when she was torturing him like this he was thinking of her. Taking one of his hands from her hips, she moved it across her stomach and into her wetness. Guiding his hand through her folds, he dragged two fingers through her with her hand on top of his. Pulling him away while she still could, she pulled his hand back up away from her.

"Jesus Kate, you're soaked.."

"Exactly. I'm enjoying this just as much as you. Now stop worrying that this isn't good for me and let. Me. Convince. You!" She still had the grip on his hand and moved it up to her mouth, sucking his fingers into her mouth to clean her arousal off of him.

That just reminded Castle of the throbbing erection between his legs and luckily, Kate seemed to have the same idea.

Moving back down his body, she took his length into her mouth once more, sucking as hard as she could. "Oh shit.." Castle growled, as Kate began to bob up and down _fast_ on his cock, almost pulling completely off of him and then swallowing him back down until his tip was far enough down her through for her to have to fight her gag reflex. Her teeth grazing over him on every up movement, she added her hands, one wrapping around the base of his shaft and gripping tightly, the other massaging and tickling his balls.

Castle couldn't hold back any longer, she'd teased him into ecstasy. Thrusting his hips upwards, his hands tangled in her hair as he fucked her mouth. "Fuck..oh _fuck_.." She took him deeper still, desperate to please him as best she could. "Shit..baby I'm gonna come..any second.." He warned, wanting to give her the chance to finish him off with her hand instead.

"In my mouth, Castle." She mumbled around him, her mouth too full to speak properly. That was enough for Castle, the vibrations from her words coupled with the words she had spoken and he was a goner. He pressed her down further onto his cock as his hips thrust up, and with one final shout he spurted into her mouth over and over again. "Oh my god.." He gasped. Kate didn't pull away, not once. She continued to suck and squeeze with every thrust of his hips as his orgasm ripped through him, swallowing down every drop of his cum. When he finally started to soften in her mouth, she cleaned the rest of his cock and released him from her mouth.

Sliding back up his body, she curled herself into his side, listening to his laboured breathing that he still couldn't get under control. Five minutes later and he had the energy to speak. "Wow, Kate. Just..wow."

She smiled and snuggled further into him. "So you liked it?"

"Liked it? It was incredible, absolutely mind blowing." He said, kissing the top of her head.

"Good, I'm glad." She whispered. She loved this man with all her heart and all she wanted was to make him happy in as many ways as possible.

"But uh..you didn't..um-"

She cut him off with a laugh. "It's fine, Castle, I'm fine, I can sort myself out. That was about you, remember?"

"Yes and mighty good job you did but I'll be damned if I leave my to fiancé to 'sort herself out'." He growled, the thought of her getting herself off both frustrating and _fucking hot._

"Oh, so you don't want to watch while I make myself come, thinking of you then?" She teased, slipping away from him and sliding her hands over her body, teasing her nipples. They hardened and she groaned, pinching them harder. "Oh god, Castle.." She moaned, "it feels so good!" She was so turned on from the blow job she'd just given Castle that she wouldn't need much to fall apart.

"Come back here, you.." He hissed, reaching for her and pinning her underneath him on the bed. His cock was springing back to life already, something that didn't go unnoticed by Kate.

"Ready to go again already? Now that's impressive.." Kate said in her best 'fuck me' voice. She was impressed though, just twenty minutes ago he'd come in her mouth harder than ever before, she didn't expect him to be able to go again so soon.

"Yeah well, when you've got the sexiest women to walk the earth about to get herself off in your bed right next to you, certain things stand up to watch." He whispered in her ear. He pinned her wrists above her head with his left hand and his right drifted down to slide through her wetness.

"Castle.." She mewled, desperate to come. She'd been turned on since they'd come into the bedroom, she was extremely impressed she hadn't either gotten herself off or given up in teasing him and fucked him into an oblivion.

Castle briefly contemplated teasing her just like she'd teased him, but he couldn't do it. She was panting and wide-eyed, legs spread as far as she could and she was _soaking_. She was so turned on from what she'd done to him and yet she'd pushed it to the back of her mind in a bid to please him. If that wasn't the perfect woman then he didn't know what was. Taking his now hard length into his hand, he slid it through her wetness before thrusting into her completely.

"Shit!" She cried out, her walls clenching around him already. "Oh god, this isn't going to last long.." She hissed, growing more and more desperate to come.

Castle felt the same. Despite the earth shattering orgasm she'd given him not long ago, he was close to the edge again. She had this effect on him. Leaning over her, he sucked on her neck, her wrists still pinned above her head and thrust into her as hard as he could.

"More.." She panted, "harder..faster.." Jesus, she was going to kill him. With his free hand, Castle rubbed over her nub frantically, increasing his pace so that he was pounding into her harder than he thought possible.

She moved her left leg up to rest on his shoulder, deepening the sensation for them both. And then she was there, with Castle's fingers sliding over her clit and his cock buried deep inside her, she fell apart. She screamed his name in ecstasy, bucking her hips up involuntarily and that did it for him. Spilling into her, he bit down and sucked hard on her neck, surely leaving a mark for everyone to see.

Both of them struggling for breath, he pulled his softening cock out of her and pulled her into his side. "You okay?" He whispered.

"Better than okay. Perfect, in fact. You?" She replied with a smile.

"Never better. You're incredible, you know that?" He said, his mind still on the incredible blow job she'd given him earlier, as well as the mind blowing sex they'd just shared.

"Well, I did say we needed a really good fu-" he cut her off with a kiss.

"Mmmm and it seems you were right." He laughed.

"Does this mean we can use the font I like?" She asked, biting her lip and looking up at him.

"After that, you can have whatever you want sweetheart. Anything. You want that font? We'll go with that font. You want to get married in the spring? We'll get married in the spring." He kissed her again. He never thought it was possible to be so in love with someone..but then, Kate Beckett always brought out the the unexpected.

"I love you." She murmured against his lips. "So much. Don't you ever forget that."

"I won't, sweetheart, I promise. I love you too, god you're perfect." He replied and she laughed, curling back into his side. She wasn't really that bothered about the font. Yeah, it was her favourite of the three but if he didn't want it she'd be happy to keep looking. But she wasn't going to pass up an opportunity to try and convince him - especially not when it went like that.

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**_A/N: phew - ice water anyone? That was a lot smuttier than I planned it but I hope you enjoy it all the same! Let me know what you think, reviews are my favourite thing on earth :)_**


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